CONVERSION COEFFICIENT FOR THE ESTIMATION OF THE ADENOMA DETECTION RATE FROM THE POLYP DETECTION RATE: VALIDATION IN A REAL COLONOSCOPY SCREENING PRACTICE SETTING IN GREECE

Aims:

Adenoma detection rate (ADR) is a fundamental metric in colonoscopy quality; however, it is cumbersome to obtain as it requires the linkage of endoscopy and pathology reports. The adenoma-to-polyp-detection-rate-quotient (APDRQ) has been proposed as an easy multiplier for the estimation of the individual endoscopist's ADR from polyp detection rate (PDR), although it lacks validation in different populations and practice settings. We aimed to validate the use of the APDRQ in a real colonoscopy practice setting in Greece.

Methods:

Consecutive screening colonoscopies of average-risk individuals conducted between January 2015 and June 2018 at the Endoscopy Unit of the Konstantopoulion General Hospital (Athens, Greece) were retrospectively evaluated. The actual ADR and PDR were calculated for each endoscopist and the weighted averaged ADR to PDR ratio for all the endoscopists was used to calculate APDRQ. The APDRQ was then used as a conversion multiplier to estimate each endoscopist's ADR from his/her PDR [estimated ADR = actual PDR x APDRQ].

Results:

A total of 1505 individuals were analyzed. The average PDR for the whole endoscopist group was 31.4% (range: 13% to 38.1%), whereas the average actual ADR was 20.4% (range: 13%-28.1%). Based on the weighted averaged ADR to PDR ratio for all the endoscopists, the APDRQ was estimated to 0.65. The average estimated ADR was 21.9% (range: 12.7%-30.2%). There was a strong correlation between actual ADR and the estimated ADR (Pearson correlation = 0.95).

Conclusions:

In a real colonoscopy screening practice setting, the ADR of an individual endoscopist can be reliably estimated from his/her PDR using an easily applied conversion coefficient.